Multiple contact device



Oct. 6, 1959 R. A. FLETCHER MULTIPLE CONTACT DEVICE Filed Nov. 29, 1957 Q ml 8 A L l l I I I I s 8 IO m w 0 Q i ll 5 8 PW Q5 INVENTOR.

Q film 4, $4 2114 BY I 5%, 1mm 7 ATTORNEYS United States Patent Ofice 2,907,867 Patented Oct. 6, 1959 MULTIPLE CONTACT DEVICE Roland A. Fletcher, San Diego, Calif. Application November 29, 1957, Serial No. 699,786

11 Claims. (Cl. 219-87) The present invention relates to a multiple contact device including two or more contacting elements which are adapted to press with equal force against another object or other objects, and more particularly to a multiple contact device of the electrical type wherein contact pressure is applied by two contacts, at equal pressure, on another object or other objects.

The present invention is particularly applicable to devices used for electric welding wherein a plurality of contacts simultaneously engage the work to be welded.

In carrying out the present invention, I provide a de vice having two or more contact elements. Some or all of these contact elements are mounted for movement independently of one another so that when they are being contacted by the work or moved into contact with the work, one or all may be shifted. The shifting, relative to one another, however, is resisted by a flexible container containing a fluid, the element or elements being in abut ting relationship with the container.

Preferably all of the contact elements are in abutting 9 relationship With the container, whereby all are subjected to the same pressure. And, preferably, the fluid employed is a gas, and can be air. The contact pressure between the contacting elements and, for example, the work to be welded, can be varied by adjustably varying the pressure of the gas in the flexible container.

More specifically, I provide a carriage for translating all of the contacting elements, in one direction, simultaneously. Each contacting element is movable independently of the others and each is in abutting relationship with the flexible container, which latter is carried by and is moved with the carriage. Should one of the contacting elements engage the work prior to the other, it will tend to exert a greater force on the flexible container than the force being applied to the others by the container, tending to compress the container with the result that increased pressure is exerted by the container on the said other contact elements, thereby forcing all the others forwardly and substantially equalizing the contact force of all contact elements on the work.

Further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the invention is illustrated.

In the drawings:

Fig. 1 is a diagrammatic top plan view of a simple form of the present invention, part thereof being broken away to show details; and

Fig. 2 is a longitudinal sectional view taken along the line 2-2 of Fig. 1.

Referring more in detail to the drawings, the multiple contact device 20 includes a base 22. The top of the base, toward the left end, carries two parallelly arranged and longitudinally disposed tracks 24 and 26, and the central top portion of the base carries two parallelly arranged and longitudinally extending tracks 28 and 30. ,A carriage 32 is slidably mounted on the top of the base and is guided by the tracks 24, 26, 28 and 30.

The carriage 32 includes a casing 34 which is formed of a left end member 36, a right end member 38 and two intermediate members 40 and 42. The casing 34 houses an inflated container 44 in the form of a tube. This container is formed of any suitable flexible material such as rubber and is preferably rectangular in shape and crosssection. The carriage also includes side members 46 and 48 for closing the ends of the members 36, 40 and 42. These side members 46 and 48 extend to the right of end member 36 to form the sides for guide plates 50 and 52. Like end members 36, 40 and 42, the guide plates 50 and 52 extend transversely of the base. Plates 50 and 52 and end member 36 are formed of insulating material, and form guides for contacting elements 54, 56, 58, 60, 62 and 64. These contact elements are elongated and are slidably mounted in the guide plate 52 and the end member 36. The rear ends 66 of these contact elements are in abutting relationship with the left side of the container 44. Shoulders 68 are formed on each of the contacting elements, and these shoulders are held inabutting relationship with the right side of guide plate 56 under pressure from the flexible container 44.

The side members 46 and 48 are provided with shoes or runners 70 and 72 respectively, which slide underneath the tracks 24 and 26 and are guided by these tracks. The'carriage 32 also includes a U-shaped runner '74 disposed to the right of the casing 34 and is suitably attached to the under side of easing member 38 as by rivets 76. The runner is provided with cars '78 which extend below the tracks 28 and 30, and is thereby guided in its longitudinal movement. The right end of the runner 74 carries uprights which are pivotally connected to a link 82 as by pin 84, and this link is connected by a pin 86 to a bell crank lever 88. This bell crank lever is pivoted by pin 90 to the base. It will be seen that when the bell crank lever is moved by its handle 92 in a counterclockwise direction, the lever arm 94 thereof will be moved downwardly, pulling downwardly on the right end of link 82 and forcing the carriage 32 to the left.

Theoretically the ends of all of the contacting elements should strike the work simultaneously, however, due to irregularities in the work simultaneously, however, due to of the contacting elements, one or more of these contacting elements may engage the work prior to others. In some types of Work being performed, such prior contacting is highly detrimental. For example, if the multiple contact device is used for welding and the contacting elements are electrodes, the result is that the metal is burned by those electrodes which engage the work prior to others and poor welds are formed by the said others. I have shown the present invention as a multiple electrode welding device, in which the contacting elements are electrodes and are connected through the connecting box 96 by conductors 98. Conductor box 96 is suitably connected to a transformer by the wire 100. The cooperating electrodes are shown at 102 which are carried by an insulating block 104 and are fed through a bus bar 106 by a wire 108.

In accordance with the present invention, should one of the contacting elements engage the work prior to the other, it will be held stationary, while the others continue to move to the left, and, being held stationary it will tend to exert a greater force on the flexible container than the force being applied to the others by the container, thereby tending to compress the container, with the result that increased pressure is exerted by the container on the said other contact elements, thereby forcing all of the others forwardly and equalizing the contact force of all contact elements on the work. The contact 3 pressure of all the contacts on the work, being substantially equal, the welds performed by each of the contacts are equal.

Preferably the fluid in the container is a gas, for example air. The resistance offered by the flexible container 44 can be adjusted by varying the pressure within the container, and this is accomplished through an abutting plate 110 which is pressed against the right side of the container, and its position, relative to the container 44, can be adjusted by a screw 112. This screw is threaded in the end plate 114 of end member 38. The knob for adjusting the screw is shown at 116.

While the form of embodiment herein shown and described constitutes a preferred form, it is to be understood that other forms may be adopted falling within the scope of the claims that follow.

I claim:

1. A multiple contact device comprising two contacting elements, one of said contacting elements being movably mounted relative to the other; and means for resisting said relative movement comprising a container containing a gas, said container including a flexible wall said relatively movable contacting element being in abutting relationship with the flexible wall of the container.

2. A multiple contact device as defined in claim 1, characterized in that both of the contacting elements are in abutting relationship with the flexible wall of the container.

3. A multiple contact device as defined in claim 1, characterized in that the flexible container contains a gas, and further characterized to include means for adjustably varying the pressure of the gas.

4. A multiple contact device comprising two contacting elements, one of said contacting elements being elongated; means supporting said elongated contacting element for movement longitudinally relative to the other and to its elongation, the front ends of said contacting elements each providing a contact; and means for resisting said longitudinal movement of the movable contacting element comprising a container containing a gas, said container including a flexible wall a part of said movable contacting element, rearwardly of the front end thereof, engaging the flexible wall of said container.

5. A multiple contact device comprising two substantially parallelly arranged contacting elements; means supporting at least one of said contacting elements for longitudinal movement relative to the other; and means for resisting said relative movement comprising a container containing a gas, said container including a flexible wall said relatively movable contacting element being in abutting relationship with the flexible wall of the container.

6. A multiple contact device comprising two substantially parallelly arranged contacting elements; means supporting both of said contacting elements for independent longitudinal movement relative to one another; and means for resisting said relative movement comprising a container containing a gas, said container including a flexible wall, said relatively movable contacting element being in abutting relationship with the flexible wall of the container.

7. A multiple contact device comprising two contacting elements; means for supporting one of said contacting elements for movement in opposite directions relative to one another; means for moving both of said contacting elements simultaneously in one of said directions; and means carried by the second mentioned means for resisting said relative movement comprising a container containing a gas, said container including a flexible wall said relatively movable contacting element being in abutting relationship with the flexible wall of the container.

8. A multiple contact device comprising two contacting elements; means for supporting both of said contacting elements for movement in opposite directions independently of one another; means for moving both of said contacting elements simultaneously in one of said dircctions; and means carried by the second mentioned means for resisting said independent movement comprising a container containing a gas, said container including a flex ible wall; said contacting elements being in abutting relationship with the flexible wall of the container.

9. A multiple contact device comprising two elongated contacting elements; a carriage supporting the contacting elements for independent movement in longitudinal directions and for simultaneously translating both contact elements longitudinally; and means carried by the carriage for resisting said independent movement comprising a container containing a gas, said container including a flexible wall said contacting elements being in abutting relationship with the flexible wall of the container.

10. A multiple contact device, as defined in claim 9, characterized in that the front ends of the contacting elements form contacts and the rear ends of the contacting elements are in abutting relationship with the container.

11. A multiple contact device, as defined in claim 9, characterized in that the front ends of the contacting elements form contacts and the rear ends of the contacting elements are in abutting relationship with the container, and further characterized to include means for adjustably varying the pressure of the gas in the container.

References Cited in the file of this patent UNITED STATES PATENTS 1,918,222 Gilbert July 13, 1933 2,256,246 Geibel Sept. 16, 1941 2,378,697 Geibel June 19, 1945 2,474,593 Putnam June 28, 1949 

